寬頻手機天線之微小化設計

Abstract

目前天線設計以滿足小尺寸與多頻帶兩大要求為主。多頻帶、小尺寸、天線場型及增益都是設計天線時重要的考量因子。然而這些因子彼此之間可能會相互衝突，所以設計時必須適當的折衝與取捨。本篇論文提出一個具有寬頻與小尺寸特性的天線，可以適用於 GPS，GSM 1800，PCS，3G，WLAN，與 WiMAX 等系統應用。該天線應用二項式曲線結構，能夠輕易滿足寬頻特性，並可藉由改變天線幾何形狀增加共振長度，達到微小化的目的。經由模擬與量測結果之比較，該天線的操作頻帶涵蓋 1.54 GHz 到 2.73 GHz，頻寬為 1.19 GHz。天線的體積為 25×25×0.8(500) ，小於文獻中其它天線設計的體積：600 , 1135 , 1181 或1598 。除此之外，這個天線具有近似單指向的(Omni-directional)輻射場型，且具有合理之增益，量測最大值介於2.25 dBi-3.74 dBi之間。

In nowadays, antenna design mainly focuses on size reduction and multi-band or broadband. However, in the design, multi-band, size reduction, radiation pattern, and antenna gain are the major issues to be considered. It is well-known that these issues are trade-offs one another. In the thesis, a broadband small antenna has been proposed for GPS, GSM 1800, PCS, 3G, WLAN, and WiMAX systems. By applying binomial curve structure, the proposed antenna can easily achieve a broad bandwidth. The miniaturization is achieved due to an increasing resonant length by properly adjusting geometrical parameters of the antenna. The simulated and measured results confirmed that the proposed antenna can operate at 1.54 GHz to 2.73 GHz bands with bandwidth of 1.19 GHz. The antenna occupies a compact volume of 25×25×0.8 , which is smaller than other designs of the volumes: 600 , 1135 ,1181 or 1598 . Moreover, the antenna has a nearly omni-directional radiation pattern and a reasonable peak gain of 2.25 dBi to 3.74 dBi.